In "Let's Play Truth or Dare", Kaeloo fell in love with Eugly. However, she left her since Quack Quack was also in love with her, and Kaeloo wanted him to be happy. In "Let's Play Tutus Galore", Kaeloo is seen laughing at the prospect of Eugly becoming a ballerina, and before the ballet recital, says that if anything goes wrong, they can blame it on Eugly. In most other episodes, Kaeloo is nice to Eugly, though they don't interact much.
Eugly is usually nice to Kaeloo. In "Let's Play Castaways", she was willing to rescue Kaeloo and the others from the island they were stranded on. In "Let's Play the Very Special Episode", Eugly laughs when Olaf tells Kaeloo to shut up after she tries to greet them. They don't interact much, but they seem to have a good relationship in general.